Iridomyrmex splendens

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Iridomyrmex splendens
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dolichoderinae
Genus: Iridomyrmex
Species: I. splendens
Binomial name
Iridomyrmex splendens
Forel, 1907

Iridomyrmex splendens side view

Iridomyrmex splendens top view

Synonyms

Iridomyrmex splendens is most common in southern Western Australia and south-eastern South Australia (including Kangaroo island), but also occurs in northern Western Australia, Victoria, Tasmania and New South Wales. Throughout much of its range, this is an ant of dry sclerophyll woodland. Nests are commonly found under logs, and workers are often seen foraging on tree-trunks and low vegetation. However, populations of the ant have also been recorded from eucalypt forest near the peaks of some of New South Wales’ higher mountains (e.g., Mt Canobolas, Mt Kaputar and Point Lookout).

Identification

Iridomyrmex splendens is one of about a dozen small-medium variegated brown to black Iridomyrmex that are superficially very similar and, in some cases, sympatric. This species can generally be recognised by the mesosomal vestiture of short, pale, bristly setae and row of short, erect setae on the posterior margin of the head (one or a few randomly distributed setae are present in the very similar Iridomyrmex mjobergi and Iridomyrmex meridianus). In difficult cases, the eye size is often decisive (see Iridomyrmex mjobergi). Workers usually possess a greenish-yellow or bluish iridescence over the entire body (present only on the gaster in Iridomyrmex victorianus, which also has a concave posterior margin of the head, whereas this margin is planar or only weakly indented medially in I. splendens), but may be a bicoloured, variegated brown-and-black or even brown-and-orange. In Tasmania, where I. splendens is sympatric with Iridomyrmex mattiroloi, it can readily be distinguished from that ant by the longer antenna and the less truncate propodeum. The form described as I. vicinus represents the larger, eastern states phenotype of I. splendens, but can readily be associated with the western form by virtue of the small eye, evenly rounded propodeum and appressed and erect pilosity pattern. These features also distinguish these nominal taxa from the very similar I. victorianus.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Australasian Region: Australia (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Castes

Worker

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • splendens. Iridomyrmex mattiroloi var. splendens Forel, 1907h: 290 (w.) AUSTRALIA. Raised to species: Heterick & Shattuck, 2011: 139. Senior synonym of vicinus: Heterick & Shattuck, 2011: 139.
  • vicina. Iridomyrmex vicina Clark, 1934c: 62, pl. 4, fig. 22 (w.q.) AUSTRALIA. Junior synonym of splendens: Heterick & Shattuck, 2011: 139.

Type Material

Description

Worker Description. Head. Posterior margin of head planar to weakly concave; erect setae on posterior margin in full-face view set in a row; sides of head noticeably convex; erect genal setae absent from sides of head in full-face view (one to a few small setae may be present near mandibular insertion). Ocelli absent; in full-face view, eyes set at about midpoint of head capsule; in profile, eye set anteriad of head capsule; eye semi-circular, or asymmetrical, curvature of inner eye margin more pronounced than that of its outer margin. Frontal carinae straight; antennal scape surpassing posterior margin of head by approximately 2 x its diameter. Erect setae on scape absent, except at tip; prominence on anteromedial clypeal margin present as an indistinct swelling or undulation; mandible triangular with distinct angle between masticatory and basal margins; long, curved setae on venter of head capsule absent. Mesosoma. Pronotum moderately and evenly curved over its length. Erect pronotal setae moderate in number (6–12), short and bristly. Mesonotum sinuous, or straight, or evenly curved. Erect mesonotal setae moderate in number (6–12), short and bristly, or sparse (6 or fewer) and bristly. Mesothoracic spiracles always inconspicuous; propodeal dorsum smoothly and evenly convex; placement of propodeal spiracle mesad, more than its diameter away from propodeal declivity; propodeal angle weakly present or absent, the confluence of the dorsal and declivitous propodeal faces indicated, if at all, by an undulation. Erect propodeal setae numerous (12 or more), short and bristly. Petiole. Dorsum of node convex; node thin, scale-like, orientation more-or-less vertical. Gaster. Non-marginal erect setae of gaster present on first gastral tergite; marginal erect setae of gaster present on first tergite. General characters. Allometric differences between workers of same nest absent. Colour shining medium brown to dark blackish-brown, weak yellowish to bluish iridescence on head and body. Colour of erect setae pale yellow to whitish.

Measurements. Worker (n = 5)—CI 84–90; EI 23–29; EL 0.18–0.19; EW 0.14–0.15; HFL 0.80–1.05; HL 0.77–0.92; HW 0.65–0.82; ML 0.9 1–1 .24; MTL 0.62–0.76; PpH 0.13–0.17; PpL 0.40–0.51; SI 105–108; SL 0.68– 0.86.

References